Valve for percussive tools.



L. c. 'BAYLES.

VALVE FOR PERCUSSIVE TOOLS. APPUCATION .HLED MAR. 6. i915.

1,222,353. PatentedAp1-.1O,1917.

WITIVESSESI: j INVE/ITOH WM $22; 0. vs LL fill, M BY ATTORA/E UNITEDSTATES PATENT .v OFFICE.

* i r W l LEWIS C. BAY LES, OF EAS'ION, PENNSYLVANIA, ASSIGNOR TOINGERSOLL-RAND COM- IANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OFNEW JERSEY.

VALVE FOR PERGUSSIVE TOOLS.

To all whom it may concern:

Be it known that I, LEWIS C. B'AYLES, a citizen of the United States,residing at Easton, in the county of Northampton and State ofPennsylvania, have invented a certain new and useful ImprovementingVal-ves for Percussive Tools, of which the'following is aspecification.

This invention relates to fluid operated percussive tools, and moreparticularly to tools of the type wherein the piston has two rearwardpressure surfaces and one forward pressure surface, oneof the rearwardpressure surfaces being subjected to constant pressure and the other twosurfaces being subjected to intermittent pressure.

The object of the present invention is to provide a tool of this type inwhich the admission of fluid to the intermittently supplied rearwardsurface of the piston is controlled by a valve whereby the admission offluid to this surface iscontinued for a longer time during the forwardstroke than during the rearward stroke ofi 'the piston, an increase inpower and efficiency being thus obtained. This object is secured bythe'invention, a practical embodiment of which .is shown in theaccompanying drawings, in

which,

Figures 1 and 2 show diagrann'mitic representations of the tool with'the moving parts in different positions, and,

Fig. 3 shows the valve 10 in detail. The tool,as shown, comprises acylinder 1,

in which is a forward cylinder bore 2 of large diameter and arearwardcylinder bore 3 of smaller diameter. Sliding 1n the; cylinder 11s a piston which has a head l fitting the forward bore 2 and a smallershank 5 fitting the rearward bore 3. The operating fiuid is admittedconstantly to the rearward end of therbore ,3 through an inlet passage(3. To supply fluid for the rear end of the forward bore 2 a passage 7leads "to a chamber 8 from the forward face of which a passage 9 leadsto the rearward end of the bore 2. To control the passage 9 a valve 10is provided. This valve 10 slides in a bore extending rearwardly fromthe cha1nher 8 and has a forward "portion 11 of smaller diameter whichserves to-control the rearward opening of passage 9, and a rearwardportion or head 12 of larger diameter which slides iira bore or closedcylinder 13. From the side of bore 3 at-Ja point uncovered ISpecification of. Letters Patent.

Patented Apr. 10, 1917'.

Application filed March 6, 1915. Serial No. 12,680.

by the shank of the piston soon after it starts to move forward, a port14 leads to the rear end of bore 13, while a leak passage 15 of smallersize than the port 14 leads to the atmosphere from the rear end of bore13. A similar leak port 16 also leads to atmosphere'from the forward endof bore 13. To convey fluid to the forward end of the bore 2 a passage17 is provided which leads from a point in the side of the bore 3uncovered by the pistonnear the end of its forward stroke to the forwardend of the bore 2-. To exhaust the fluid from the front and rear ends ofthe bore 2 a main exhaust passage 18 and two auxiliary exhaust passages19 and 20 are provided, these auxiliary exhaust passages 19 and 20 beingcontrolled by an-exhaust valve 21, the details of this exhaustcontrolling mechanism forming no part of the present invention, beingfully described in the copending application of '1. M. Slater, SerialNo. 879,860, filed Decen'iber 31st, 191st.

In the operation of the tool, supposing the pafrts to be in thepositions shown in Fig. 2 fluidis being admitted to the rear of bore 2'through the passage 7, chamber 8, and

,passage 9, the'valve 10. being in its rear-most on its front surface bythe fluid in the chamber 8, the port 14 at this time being closed by thepiston shank 5. -The exhaust valve 21 will be in the position shown,cutting off the exhaust from the fear end of the bore 2. As the pistonmoves forwardly, the rear end of the shank 5 will uncover the port 14after the piston has traveled but a short distance. This will admitpressure to the rear end of the bore 1.3, and as the rear surface of thevalve 10 is larger than its forward surface, the valve 10 will'be movedforwardly, cutting oil the opening to passage 9 from the chamber 8, andthus cutting off the admission of fluid to the rear end of the bore 2.The piston will continue to move forward under the constant pressure onthe rear surface of the shank 5 and the expansion of the fluid in therear end of the bore lVhen the rearend of the shank 5 uncovers therearward openingof the passage 17, fluid will be admitted from the bore3 into the forward 'end of bore 2, at the same time the rear edge ofpiston head will uncover the main exhaustpassagelS. This will move theexhaust valve 21 to the BEST AVAILABLE cop fluid in the forward end ofthe boreQ act-- ing expansively when the admission through the passage17 is cut off. The valve 10 will remain in the position shown in Fig. 1until after the rear end of the shank 5 closes the port 14. When thisport 14 is closed the pressure on the rear surface of the valve willfall due to the fluid escaping through the leak port 15. As the onlyforce tending to move the valve rearwardly is the pressure of the fluidin chamber 8 against the small annularshoulder on the forward por-' tionof the valve 10, the pressure in the rear end. of the bore 13 will haveto fall almost to atmOsPheric pressure before the valve 10 will start tomove, this pressure being reached before the piston reaches the endoflits stroke, but when the valve is once started the intake pressurewill be exerted on the whole forward face of the valve 10,

. causing the valve tocomplete its travel very quickly. The exhaustvalve 21 will moreover be shifted by the escaping fluid so as to closethe exhaust passage 19 as soon as the pressure in passage 20 is relievedby the piston head 4 uncovering the main exhaust 18, thus causingcompression between the piston head 4 and the end of the cylinder whichwill be exerted on the forward surface of portion 11 of thevalve andwill insure the valve opening beforethe piston reaches the end of thecylinder. The leak port 16 is provided to allow the valve 10 to havefree movement in either direction, as far as any ressure in the forwardend of the bore 13 1S concerned. It will be seen that by thisconstruction, although the valve 10 moves forwardly to close off thepamage 9 immediately the port 14 is uncovered by the piston during itsforward stroke, the movement of the valve 10 rearwardlywhen the port 14is again covered by the piston on its rearward stroke will be subject'toa lag due to the fact that the fluid in the rear end of the bore 13 mustescape to the atmosphere. The movement of the valve thus permits theadmission of fluid to the rear end of the bore 2 to be continued longerduring the forward stroke of the piston than during the rearward stroke,a greater power in the operation of the tool being thereby obtained.

It is to be understood that while the present showing and descriptiondiscloses only one specified modification of the present invention,other forms and modifications are included in the spirit and scope ofthe same,-

as expressed in the appended claims.

What I claim is:

1. In a fluid operated percussive tool, a

, inder ,COIDPI'IBIDK cylinder, a piston therein having two rearpressure surfaces and one fonvanlpressure surface, means for admittingfluid to the cylinderto exert a constant pressure on one of saidrearward surfaces, a conduit indeo pendent of the piston for conveyingfluid to exert an intermittent pressure on the other of said rearpressure surfaces, a valve controlling said conduit, a conduitcontrolled by said piston for conveying fluid to exert 15 anintermittent pressure on the forward surface of said piston and exhaustmeans for the intermittently supplied portions of the cylinder.

2. In a fluid operated percussive tool, a cylinder, a piston thereinhaving two rear pressure surfaces and one forward pressure surface,means for admitting fluid to the cylinder to exert a constant pressureon one of said rearward surfaces, a conduit independent of the pistonfor conveying fluid to exert an intermittent pressure on the other ofsaid rear pressure surfaces, avalve controlling said conduit, a conduitcontrolled by sai piston for conveying fluid to exert an intermittent'pressureon the forward surface of said piston and exhaust means for theintermittently supplied portions of the cylinder, comprising anindependent exhaui valve, i

3. In a fluid operated percussive tool, a cylinder having a largerforward bore and a smaller rearward bore, 'a'piston having a headfitting said larger bone and a shank fittin said smaller bore, an inletfor admitting uid constantly to the rear end of said smaller bore, apassage independent of the piston from said inlet to the rear end ofsaid largerbore, a valve controlling said assage to admit fluid to therear end of said la r 10! bone only near the rearward end of the plltonstroke, means for conveying fluid mm mittcntly to the forward end ofsaid larger bore, and means for exhausting the intermitv I tentlysupplied portions of the cylinder.

4. In a fluid operated ussive tool, a cylinder having a larger orwardbore and a smaller rearward bore, a piston villi! head fitting saidlarger bore and a shank tting said smaller bore, an inlet for admitti I116 fluid constantly to the rear end of smaller bore, a passageindependent of the piston from said inlet to the rear ends,- said largerbore, a valve controlling assage to admit fluid to the rear end of 1arger bore only near-the rearward and of the piston stroke, means forconveiing fluid I intermittently to the forwarden '0 said v larger bore,and means for exhausting the intermittently supplied portions of thecyl- 1 all independent exhum valve. I

5. In I fluid rated percussive tool a cylinder having a lirger forwardore an a smaller rearward a piston, "180 ward pressure surface,

head fitting said largerbore and a shank fitting said smaller bore, saidpiston having two rearward pressure surfaces and a formeans foradmitting fluid constantly to exert a pressure on one of said rearwardpressure surfaces, a passage independent of the piston from. theconstant pressure portion of the cylinder to convey fluid tov exertpressure on the other of said rearward pressure surfaces, a valvecontrolling said passage', means, for moving said valve to open saidpassage near the end of the rearward stroke of said piston, and to closesaid passage after said piston has traveled forward a short distance onits forward stroke, means for intermittently conveying fluid to theforward end of the cylinder and means for exhausting said intermittentlysupplied cylinderportions.

6. In a fluid operated percussive tool, a

. cylinder having a smaller rearward bore and a larger-forward bore, apiston'having a head fitting said larger bore and ,a shank fitting saidsmaller bore, meansfor constantly admitting fluid to the rear end ofsaid smaller bore, a conduit independent of the piston from the rear endof said smaller bore to the :rear end of said larger bore, a valve forcontrolling said conduit, having operating surfaces, a port opened bysaid piston for conveying fluid to an operating surface of said valve tomove said valve to close said conduit when said piston has traveled ashort distance on its downward stroke, means for moving said valve toopen said conduit near the rear end of said piston rearward stroke,means forconveying fluid intermittently to the forward end of saidlarger bore and meansfrom the ends of said larger bore. i

7. In a fluid operated percussive tool, a cylinder having asmallerrearward bore and a larger forward'bore, a piston having a headfitting said larger bore and a shank fiting said smaller bore, means forconstantly admitting fluid to the rear end of said smaller bore, aconduit independent of the piston from the rear end of said smaller boreto the rear end of said larger bore, a. valve for controlling saidjconduit, having operating surfaces, a port opened by said piston forexhausting fluid for conveying fluid to an operating surface of saidvalve to move said valve to close said conduit when said piston hastraveled a short distance on its downward stroke, means for moving saidvalve to open said conduit near the rear end of said piston rearwardstroke, means for conveying fluid intermittently to the f? ard end ofsaid larger bore and means 0" exhausting fluid from the ends of saidlarger bore, comprising a separate fluid controlled exhaust valve.

8. In a fluid operated percussive tool, a cylinder having a two diameterbore, a piston having a head fitting the larger bore and a shank fittingadmitting fluid constantly against one face of said piston to drive thepiston in one direction, ton for conveying fluid to exert'anintermittent pressure on another face of the piston to drive it inthe'same direction as the constant pressure, a valve controlling saidconduit, a conduit controlled by the piston for intermittently conveyingfluid to a piston face opposed to the said two faces and exhaust meansfor relieving the pressure from the intermittently supplied faces of thepiston.

9. In a fluid operated percussive tool, a cylinder, a piston thereinhaving two pressure surfaces facing the same way, and an opposedpressure surface facing the oppo: site way, means for admitting fluid tothe cylinder to exert a continuous pressure on one of said two pistonsurfaces, a conduitindependent of the piston for conveying fluid toexert an intermittent pressure on the other of said two piston surfaces,a valve controlling said conduit, a conduit controlled by the piston forconveying fluid to exert an intermittent pressure on the opposed pistonsurface and exhaust means for the intermittently supplied portions ofthe cylinder.

In testimony whereof, I have hereunto set my hand.

LEWIS o. BAYLns. Witnesses:

FRED. M. SLALns, Ronnn'r L. AMBRosn.

the smaller bore, an inlet for a conduit independent of the pis-

